Effects of Aminobisphosphonates and Thiazides in Patients With Osteopenia/Osteoporosis, Hypercalciuria, and Recurring Renal Calcium Lithiasis

Risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones: a cross-sectional study

Low femoral neck bone mineral density (BMD) was associated with the increased risk of kidney stones. Low dietary magnesium intake and increased serum alkaline phosphatase were associated with the increased risk of low femoral neck BMD in kidney stone formers.

PURPOSE

To evaluate whether low femoral neck bone mineral density (BMD) was associated with a higher risk of kidney stones, and identify risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones.

METHODS

We analyzed individuals aged ≥ 20 years from National Health and Nutrition Examination Survey 2007-2020 data. Osteoporosis/osteopenia is defined as any T-score < -1.0 of femoral neck, total femoral, and mean lumbar spine (L1-L4) BMD. Dietary intakes (sodium, potassium, magnesium, calcium, phosphorus, calcium/phosphorus, vitamin D (25OHD2+25OHD3)) and serum parameters (sodium, potassium, calcium, phosphorus, bicarbonate, vitamin D, alkaline phosphatase (ALP)) were screened for identifying risk factors for the comorbidity.

RESULTS

The prevalence of comorbidity of osteoporosis/osteopenia and kidney stones was 4.82%. Femoral neck BMD T-score was negatively associated with the prevalence of kidney stones (n=11,864). Dietary magnesium intake, serum phosphorus, and bicarbonate were negatively associated with the comorbidity prevalence, and serum ALP was positively associated with the comorbidity prevalence (n=6978). Additionally, there remain significant associations of dietary magnesium intake, serum ALP, and bicarbonate with not only femoral neck BMD T-score (n=11331), but also the prevalence of kidney stones (n=23,111) in general population. Furthermore, dietary magnesium intake was positively correlated to femoral neck BMD T-score in stone formers (SFs), while serum ALP was negatively correlated to femoral neck BMD T-score in SFs (n=1163).

CONCLUSION

Low femoral neck BMD was closely associated with an increased risk of kidney stones. Low magnesium intake and increased serum ALP were associated with the increased risk of the comorbidity, as well as indicative of low femoral neck BMD T-score in SFs, which offered a clue to further clarify the mechanism leading to paradoxical calcification of bone resorption and kidney stones, and had the potential to perform personalized diagnostic workup for low BMD in SFs.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

Bisphosphonates and management of kidney stones and bone disease

PURPOSE OF REVIEW

Kidney stones are strongly associated with low bone density and bone fracture. Clinical management focuses on prevention of kidney stones and bone fracture. We reviewed literature of kidney stones and bone disease with a special focus on updates in therapeutic strategies. We will review the literature regarding dietary management, supplements, and medications and emphasize the recent studies on bisphosphonates and kidney stone management.

RECENT FINDINGS

Bisphosphonate medications are commonly used in management of low bone density. Previous studies showed that they reduce urinary calcium. A recent large prospective study found that bisphosphonates may reduce the risk of kidney stones in individuals who have low bone density. In addition to lowering urinary calcium, a recent study found that bisphosphonates may act as an inhibitor in the urinary space.

SUMMARY

There are multiple dietary and pharmacologic strategies that can be considered for kidney stones and bone disease, such as low salt and normal calcium diet, as well as thiazides, alkali, and bisphosphonate medications. Bisphosphonates may have an important role in reducing bone resorption and reducing overall risk of kidney stone and bone disease.

Effects of bendroflumethiazide on bone mineral density; results from the BONATHIAD randomized double-blind placebo-controlled cohort study

Purpose

Thiazide diuretics (TD) may play a role in preventing osteoporosis. The objective was to investigate the effects of bendroflumethiazide in combination with bisphosphonates on bone mineral density, selected blood parameters, blood pressure, pulse, and muscle function.

Methods

Double-blinded, randomized, placebo-controlled interventional study in postmenopausal osteoporotic women over the age of 50 years consisting of four arms: 1) 24 weeks with bendroflumethiazide +24 weeks of washout, 2) 24 weeks with placebo +24 weeks of washout, 3) 48 weeks with bendroflumethiazide, or 4) 48 weeks with placebo. At inclusion, participants were on oral bisphosphonates. Intervention consisted of either bendroflumethiazide or placebo. Dual energy X-ray absorptiometry (DXA), vertebral fracture assessment (VFA), quantitative CT (QCT) and selected blood parameters were acquired at baseline and at 48 weeks and Timed-Up-and-Go, handgrip strength, blood pressure, pulse and balance additionally at 24 weeks.

Results

139 postmenopausal Caucasian women over 50 years were randomized (mean age 64.7 years (SEM 0.6, range 51–79)). 109 (78%) completed the study. No difference in the effect of bendroflumethiazide on DXA, VFA, QCT, biochemistry or muscle function were found between the treatment arms.

Conclusion

Bendroflumethiazide for 24- or 48 weeks in combination with bisphosphonates does not improve bone mineral density, selected blood parameters or muscle function compared to placebo combined with bisphosphonates. Studies with longer treatment periods and more patients are needed to further characterize the effects of bendroflumethiazide on bone and subpopulations that might benefit from the treatment.

Effect of bisphosphonates on the crystallization of stone-forming salts in synthetic urine

Purpose

We investigated the inhibitory effect of bisphosphonates (BPs) on the crystallization of calcium oxalate monohydrate (COM), calcium phosphate (CaP), and magnesium ammonium phosphate (MAP) in synthetic urine, aiming to see 1) which specific BPs work best on a particular type of crystal and 2) what is the lowest concentration of BPs that inhibits crystal formation.

Materials and Methods

Crystals from synthetic urine were exposed to different concentrations of BPs. Urinary turbidity was used as a marker of crystallization and was measured by spectrophotometry by use of a validated method in our laboratory. The percent inhibitory activity (IA) was calculated by using the formula: (a−b )/a×100, where a is baseline maximal turbidity and b is maximal turbidity with various concentrations of medication. Potassium citrate and magnesium citrate were used as positive controls.

Results

At the lowest dose of 0.001 mg/mL, risedronate induced the highest IA of 37% on CaP, whereas ibandronate had the strongest IA on COM (24%). To initiate the inhibition of MAP crystallization, risedronate required a two-fold higher concentration (0.002 mg/mL) to reach 30% IA, whereas etidronate required a four-fold higher concentration (0.004 mg/mL) to reach 42% IA.

Conclusions

BPs are good inhibitors of crystallization in synthetic urine, with risedronate and ibandronate being the most potent. At a low clinically acceptable dose, their highest inhibitory action was on CaP and COM crystals. Higher doses were needed to prevent MAP crystallization. Further investigation of the use of BPs in kidney stone prevention is warranted.

Empiric therapy for kidney stones

Careful phenotyping of patients to classify those with kidney stones has a long and important history in revealing the chemical basis for stone formation. Advances in our genetic understanding of kidney stones will lead to incredible insights regarding the pathophysiology of this common disorder. At this time, both evaluation of urine chemistry and genotyping of patients are extremely useful in the setting of a university and research-based kidney stone clinic. For much of the world, in a more clinically focused setting, these techniques are neither available nor absolutely necessary. Careful implementation of an empiric prescription based on stone composition would have an important effect to reduce stone recurrence in the world's many stone formers. Increased fluid intake, generic dietary manipulations, and prescription of potassium citrate and thiazides are all appropriate empiric therapies for people with calcium and uric acid kidney stones.

CT-Based Diagnosis of Low Vertebral Bone Mineral Density Is Associated with Hypercalciuria and Hypocitraturia on Opportunistic Imaging

INTRODUCTION AND OBJECTIVES

Studies have demonstrated associations between nephrolithiasis and systemic conditions, including low bone mineral density (BMD), which may correlate with hypercalciuria in kidney stone formers (KSFs). Traditionally, low BMD is diagnosed with dual-energy X-ray absorptiometry. As a noncontrast CT (NCCT) scan is typically part of a stone evaluation, our objective was to evaluate the association of NCCT-based vertebral BMD with 24-hour urine parameters in KSF.

MATERIALS AND METHODS

This is a retrospective analysis of 99 KSFs who had CT imaging and 24-hour urine studies. For each patient, BMD was estimated at the L1 vertebral body and CT attenuation measured in HU. A threshold of 160 HU was chosen to distinguish normal from low BMD. Univariate and multivariate logistic regression analysis was performed to compare patients with low and normal BMD. Multivariate linear regression was performed to assess for variables associated with 24-hour urine parameters.

RESULTS

Patients with low BMD had higher 24-hour urine calcium (219 vs 147 mg/day, p < 0.0001) and larger stone volume (259 vs 78.4 mm³, p = 0.009). Multivariate analysis demonstrated age >60 years (odds ratio [OR] 9.3, p < 0.0001) and hypercalciuria (OR 4.34, p = 0.004) correlated with low BMD. Linear regression demonstrated that lower BMD was associated with higher urinary calcium (β-coefficient -0.268, p = 0.009) and lower urinary citrate (β-coefficient 0.332, p = 0.01).

CONCLUSIONS

CT-based diagnosis of low mineral bone density is associated with derangement in 24-hour urine calcium and citrate in KSFs, as well as larger stone volumes.

Urolithiasis is prevalent and associated with reduced bone mineral density in β-thalassaemia major

Asymptomatic urolithiasis is common and of mixed composition in patients with β-thalassaemia major. Twenty-seven subjects were imaged using dual-energy computer tomography to determine the presence and composition of urolithiasis. The prevalence of urolithiasis was 59% and affected patients generally had multiple stones, often with more than one component: struvite (33%), calcium oxalate (31%) and cystine (22%). Hypercalciuria was present in 78% of subjects and calcium-containing urolithiasis was associated with reduced femoral neck Z scores.

A contemporary therapeutic approach to bone disease in beta-thalassemia - a review

Homozygous beta-thalassemia represents a serious hemoglobinopathy, in which an amazing prolongation in the survival rate of patients has been achieved over recent decades. A result of this otherwise positive evolution is the fact that bone problems have become a major issue in this group of patients. Through an in-depth review of the related literature, the purpose of this study is to present and comment on the totality of the data that have been published to date pertaining to the prevention and treatment of thalassemia bone-disease, focusing on: the contribution of diet and lifestyle, the treatment of hematologic disease and its complications, the management of hypercalciuria, the role of vitamins and minerals and the implementation of anti-osteoporosis medical regimen. In order to comprehensively gather the above information, we mainly reviewed the international literature through the PubMed database, searching for the preventive and therapeutic data that have been published pertaining to thalassemia bone-disease over the last twenty-nine years. There is no doubt that thalassemia bone-disease is a complication of a multi-factorial etiopathology, which does not follow the rules of classical postmenopausal osteoporosis. Bisphosphonates have been the first line of treatment for many years now, with varied and usually satisfactory results. In addition, over the last few years, more data have arisen for the use of denosumab, teriparatide, and other molecules that are in the clinical trial phase, in beta-thalassemia.

Nephrolithiasis and Nephrocalcinosis in Childhood-Risk Factor-Related Current and Future Treatment Options

Nephrolithiasis, urolithiasis, and nephrocalcinosis (NC) have become common causes of hospitalization and referral to pediatric outpatient clinics. It is of utmost importance to start with diagnostic evaluation directly after the first passage of a kidney stone, or if NC is diagnosed, in each pediatric patient. This is necessary, as in about 80% of children a metabolic reason for stone disease is detected. Current treatment options are scarce and mainly include general measures like an increased fluid intake or elevating the solubility of a lithogenic substance. According to the given lithogenic risk factor(s), specific treatment options are available and are being summarized in this review. Furthermore, an outlook on potential future treatment options, including innovative strategies such as mRNA-based or recombinant enzyme substitution therapy, is given.

Low Bone Density and Bisphosphonate Use and the Risk of Kidney Stones

BACKGROUND AND OBJECTIVES

Previous studies have demonstrated lower bone density in patients with kidney stones, but no longitudinal studies have evaluated kidney stone risk in individuals with low bone density. Small studies with short follow-up reported reduced 24-hour urine calcium excretion with bisphosphonate use. We examined history of low bone density and bisphosphonate use and the risk of incident kidney stone as well as the association with 24-hour calcium excretion.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a prospective analysis of 96,092 women in the Nurses' Health Study II. We used Cox proportional hazards models to adjust for age, body mass index, thiazide use, fluid intake, supplemental calcium use, and dietary factors. We also conducted a cross-sectional analysis of 2294 participants using multivariable linear regression to compare 24-hour urinary calcium excretion between participants with and without a history of low bone density, and among 458 participants with low bone density, with and without bisphosphonate use.

RESULTS

We identified 2564 incident stones during 1,179,860 person-years of follow-up. The multivariable adjusted relative risk for an incident kidney stone for participants with history of low bone density compared with participants without was 1.39 (95% confidence interval [95% CI], 1.20 to 1.62). Among participants with low bone density, the multivariable adjusted relative risk for an incident kidney stone for bisphosphonate users was 0.68 (95% CI, 0.48 to 0.98). In the cross-sectional analysis of 24-hour urine calcium excretion, the multivariable adjusted mean difference in 24-hour calcium was 10 mg/d (95% CI, 1 to 19) higher for participants with history of low bone density. However, among participants with history of low bone density, there was no association between bisphosphonate use and 24-hour calcium with multivariable adjusted mean difference in 24-hour calcium of -2 mg/d (95% CI, -25 to 20).

CONCLUSIONS

Low bone density is an independent risk factor for incident kidney stone and is associated with higher 24-hour urine calcium excretion. Among participants with low bone density, bisphosphonate use was associated with lower risk of incident kidney stone but was not independently associated with 24-hour urine calcium excretion.

Clinical practice guidelines for posmenopausal, glucocorticoid-induced and male osteoporosis. Spanish Society for Research on Bone and Mineral Metabolism (3rd updated version 2014)

These guidelines update issues covered in previous versions and introduce new ones that have arisen in recent years. The former refer mainly to the therapeutic developments that have been made during this time (zoledronate, denosumab, bazedoxifene), which have led to a change in the drug selection algorithm. The latter deal with therapeutic management, the description of new adverse effects (which have led to changes in therapeutic behaviour patterns, as is the case with atypical fracture of the femur), treatment duration (with consideration for the so-called "therapeutic holidays"), the so-called sequential treatment and changes in treatment imposed by certain circumstances. A new algorithm has been introduced for sequential treatment. Attention has also been paid to vertebroplasty and kyphoplasty.

Calcium nephrolithiasis and bone demineralization: pathophysiology, diagnosis, and medical management

PURPOSE OF REVIEW

To establish the relationship between calcium nephrolithiasis, bone densitometry scoring, and bone mineral density (BMD) loss according to bone turnover markers (BTMs) and urinary metabolites.

RECENT FINDINGS

Patients with recurrent calcium nephrolithiasis and idiopathic fasting hypercalciuria (urinary calcium/creatinine ratio >0.11) are more likely to have BMD loss that may lead to osteopenia or osteoporosis. In these patients, BTMs may be used as a surrogate for both bone health and stone recurrence. Suspect higher lithogenic states when calcium stone formers have serum beta-crosslaps (resorptive marker) greater than 0.311 ng/ml, serum osteocalcin (formative marker) greater than 13.2 ng/ml, and beta-crosslaps/osteocalcin ratio greater than 0.024.

SUMMARY

Patients with recurrent calcium nephrolithiasis and fasting hypercalciuria have a higher incidence of osteopenia and osteoporosis, measured by the dual-energy X-ray absorptiometry. These patients present not only with hypercalciuria and increased BTMs (mainly resorptive), but also up to 30% have hypocitraturia and increased urinary calcium/citrate ratio (>0.25). On the basis of these results, a diagnostic algorithm was created, classifying hypercalciurics according to their fasting calcium/creatinine and calcium/citrate ratio. Medical therapy for these patients is aimed at improving the dietary habits (normocalcemic, low salt, low animal protein diet), prescribing combinations of potassium citrate, thiazides, and bisphosphonates, and correcting bone and urinary abnormalities that may lower future skeletal and kidney stone risk.

Vascular calcification and bone mineral density in recurrent kidney stone formers

BACKGROUND AND OBJECTIVES

Recent epidemiologic studies have provided evidence for an association between nephrolithiasis and cardiovascular disease, although the underlying mechanism is still unclear. Vascular calcification (VC) is a strong predictor of cardiovascular morbidity and the hypothesis explored in this study is that VC is more prevalent in calcium kidney stone formers (KSFs). The aims of this study were to determine (1) whether recurrent calcium KSFs have more VC and osteoporosis compared with controls and (2) whether hypercalciuria is related to VC in KSFs.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a retrospective, matched case-control study that included KSFs attending an outpatient nephrology clinic of the Royal Free Hospital (London, UK) from 2011 to 2014. Age- and sex-matched non-stone formers were drawn from a list of potential living kidney donors from the same hospital. A total of 111 patients were investigated, of which 57 were KSFs and 54 were healthy controls. Abdominal aortic calcification (AAC) and vertebral bone mineral density (BMD) were assessed using available computed tomography (CT) imaging. The prevalence, severity, and associations of AAC and CT BMD between KSFs and non-stone formers were compared.

RESULTS

Mean age was 47±14 years in KSFs and 47±13 in non-stone formers. Men represented 56% and 57% of KSFs and non-stone formers, respectively. The prevalence of AAC was similar in both groups (38% in KSFs versus 35% in controls, P=0.69). However, the AAC severity score (median [25th percentile, 75th percentile]) was significantly higher in KSFs compared with the control group (0 [0, 43] versus 0 [0, 10], P<0.001). In addition, the average CT BMD was significantly lower in KSFs (159±53 versus 194 ±48 Hounsfield units, P<0.001). A multivariate model adjusted for age, sex, high BP, diabetes, smoking status, and eGFR confirmed that KSFs have higher AAC scores and lower CT BMD compared with non-stone formers (P<0.001 for both). Among stone formers, the association between AAC score and hypercalciuria was not statistically significant (P=0.86).

CONCLUSIONS

This study demonstrates that patients with calcium kidney stones suffer from significantly higher degrees of aortic calcification than age- and sex-matched non-stone formers, suggesting that VC may be an underlying mechanism explaining reported associations between nephrolithiasis and cardiovascular disease. Moreover, bone demineralization is more prominent in KSFs. However, more data are needed to confirm the possibility of potentially common underlying mechanisms leading to extraosseous calcium deposition and osteoporosis in KSFs.